Inhibiting α1-adrenergic Receptor Signaling Pathway Ameliorates Alzheimer’s Disease Type Pathologies and Behavioral Deficits in an AD Mouse Model

Background The role of α1 adrenergic receptors (α1-ARs) signaling pathway in the pathogenesis of Alzheimer’s disease (AD) has rarely been investigated. Clarifying pathophysiological functions of α1-ARs in the AD brain is helpful for better understanding the pathogenesis and screening novel therapeutic target of AD. Methods This study included 2 arms of in vivo investigations: 1) 6-month-old female APPswe/PS1 mice were intravenously treated with AAV-PHP.eB-shRNA (ARs)-GFP or AAV-PHP.eB-GFP for 3 months. 2) 3-month-old female APPswe/PS1 mice were daily treated with 0.5 mg/kg terazosin or equal saline for 6 months. SH-SY5Y cell lines bearing human Amyloid precurssor protein were treated with terazosin or saline for investigating possible mechanisms. Results α1-ARs knockdown mice exhibited improved behavioral performances than control mice. α1-ARs knockdown mice had significantly lower brain amyloid burden, as reflected by soluble Aβ species, compact and total plaques, than control mice. The α1-ARs inhibitor terazosin substantially reduced Aβ deposition, attenuated downstream pathologies including Tau hyperphosphorylation, glial activation, neuronal loss, synaptic dysfunction, and rescued behavioral deficits of APPswe/PS1 mice. In vitro investigation demonstrated that α1-ARs inhibition down-regulated BACE1 expression, and promoted ser9 phosphorylation of GSK-3β, thus reduced Aβ production. Conclusions This study indicates that inhibition of α1-ARs signaling pathway might represent a promising therapeutic strategy for AD.